Lpg valve assembly

ABSTRACT

A conventional pressure can has a top end wall with a central aperture and a stationary tubular body fixed to the end wall and projecting axially into the interior of the can. A central threaded opening in the body communicates with the aperture and with the bore of an axial elastomeric sleeve fixed within the body. A metallic piston of cylindrical shape and rounded ends is received within the bore of the elastomeric sleeve between the ends thereof and the diameter of the cylindrical piston is greater than the normal free diameter of the bore, so that the piston prevents escape of LPG fuel from the can under normal pressure conditions but blows out through the body opening and can top aperture in the event of buildup of excessive pressure within the can due to heat. An outlet unit having external threads engaging internal threads within the body is insertable through the cap top aperture, and this outlet unit carries an axially extending projection capable of axially displacing the piston from the bore of the elastomeric sleeve into a stationary retainer tube on the body. The projection seals within the bore of the elastomeric sleeve and has a flow control side port communicating with a central axial discharge passage so that turning movement of the outlet unit relative to the can and body may expose the port below the lower end of the elastomeric sleeve in a controlled manner to regulate the flow rate through the discharge passage. Upon axial removal of the outlet unit from the body, the piston is seated by gas pressure against the lower end of the elastomeric sleeve to act as a check valve preventing escape of gas from the can. A hollow refill probe may be axially inserted through the can top aperture and body opening to displace the piston from sealing position to refill the can to the desired level, and upon removal of the probe the piston is returned by gas pressure to seal against the lower end of the elastomeric sleeve.

0 United States Patent 1191 1111 3,800,979 Piffath et al. Apr. 2, 1974LPG VALVE ASSEMBLY {571 ABSTRACT [75] Inventors: Rodney S. Piffath,Northridge; John A conventional pressure can has a top end wall with aJ. Cole, Beverly Hills, both of Calif, central aperture and a stationarytubular body fixed to the end wall and projecting axially into theinterior of [73] Asslgnee: International Flre Tool Corporamm the can. Acentral threaded opening in the body com- New York municates with theaperture and with the bore of an [22] Filed: Dec. 29, 1971 axialelastomeric sleeve fixed within the body. A metallic iston ofcylindrical shape and rounded ends is [211 App! 214396 receiv d withinthe bore of the elastomeric sleeve between the ends thereof and thediameter of the cylin- [52] U.S. Cl 220/89 A, 137/322, 137/467, dricalpiston is greater than the normal free diameter 137/DlG. 2, 220/44 B,222/3, 222/396, 251/353 of the bore, so that the piston prevents escapeof LPG [51] Int. Cl.... B65d 25/00, B65d 7/24, B65d 51/16 fuel from thecan under normal pressure conditions 58 Field of Search 220/89 A, 44 B;74/537; but blows out through the y Opening and can p 251/353, 216, 264,349; 137/322, 323, DIG. aperture in the event of buildup of excessivepressure 2, 67, 467; 141/295; 222/3, 396, 386, 386 S, within the can dueto heat. An outlet unit having ex- 81, 49 S ternal threads engaginginternal threads within the body is insertable through the cap topaperture, and [56] Referen e Cited this outlet unit carries an axiallyextending projection UNITED STATES PATENTS capable of axially displacingthe piston from the bore of the elastomeric sleeve into a stationaryretainer gligg tube on the body. The projection seals within the bore29981024 8/1961 Mama, et aL 137 52527 of the elastomeric sleeve and hasa flow control side 3,224,455 12/1965 Acfieri 137/113 P Communicatingwith a Central axial discharge P 1 275 733 3 19 g Steinmetz 13 2 sage sothat turning movement of the outlet unit rela- 3,498,313 3/1970 Belich137/322 tive to the can and body may expose the port below 3, 6 Bouvierl37/322 the lower end of the elastomeric sleeve in a controlled 8 972 an2 manner to regulate the flow rate through the discharge 3,187,9626/1965 Meshberg" 251/353 passage. Upon axial removal of the outlet unitfrom 3552421 1971 1 251/216 the body, the piston is seated by gaspressure against 3,512,754 5/1970 Zamo 251/353 h l d f th 1 t m l t t3,174,519 3/1965 Pizzurro etal. 251 353 t e Ower e as o em ac as 33,353,724 11/1967 Johnston 137/322 check valve Prevemmg escape of gasfmm the A 3,315,693 4/1967, Braun 251 /353 hollow refill Probe may beaxially inserted thmugh the 1 334 5 3 1920 Steinmetz 251 353 can topaperture and body opening to displace the pis- 2,664,266 12/1953Johnson..... 251/353 ton from sealing position to refill the can to thede- 2,6l9,982 12/1952 Turner 137/67 sired level, and upon removal of theprobe the piston FOREIGN PATENTS OR APPLICATIONS is returned by gaspressure to seal against the lower 1,293,911 4/1962 France 251/360 W?the elastomenc Sleeve Primary Examiner-George E. Lowrance AssistantExaminer-Allan N. Shoap 7 Claims, 12 Drawing Figures mimaom m SHEETZUFZr/ VI MVV LPG VALVE ASSEMBLY This invention relates to a valve'assemblyfor a LPG container and is particularly directed to a multiple purposedevice which acts first as a safety plug to prevent escape of LPG fromthe can until the can is ready for use but which will blow out underexcessive pressure caused by heat to prevent an explosion of the can;secnd, to regulate the flow of gas from the can when it is in use;third, to act as a check valve to prevent escape of LPG from the canwhen use of the can is temporarily discontinued; and fourth, to permitrefill of the can through a hollow probe when the LPG contents have beendepleted and to seal against gas escape until the can is to be usedagain. These operating characteristics of the valve assembly are highlydesirable for use with a conventional pressure can of standarddimensions for use as a fuel supply for stoves, lanterns, lighters,heaters, etc.

A conventional pressure can of standard dimensions available in quantityat low cost has a conventional pressure-tight spun joint with an, endwall which comprises the can top. In accordance with this invention,

the can top is provided with a central aperture and an aligned axiallyextending body fixed to the can top and extending axially into the can.The body is tubular and is aligned with the aperture. After initialfilling of the can with LPG by conventional apparatus, a cylindricalpiston with rounded ends is inserted into the body and into the axialbore of an elastomeric sleeve fixed in the body. The diameter of thecylindrical piston is greater than the normalfree diameter of the borein the elastomeric sleeve so that the piston is gripped between the endsof the elastomeric sleeve to prevent escape of LPG from the can undernormal pressure conditions. Should the can become overheated for anyreason, the increased pressure of the LPG forces the piston out of theelastomeric sleeve and out through the can top aperture to permitdischarge of the LPG and to prevent explosion of the can.

When the can and contents are to be used with a Stove, lantern, lighter,heater, etc., an outlet unit is inserted axially through the can vtopaperture into threaded engagement with the internal body. A cylin dricalprojection on the outlet unit mechanically displaces the piston from itssealed position and moves it out of the elastomeric sleeve into astationary retainer tube, whereupon the cylindrical projection of theoutlet unit seals within the bore of the elastomer sleeve. Turningmovement of the outlet unit and projection with respect to the bodyalong the threaded connection exposes a side port in the projection topermit flow of LPG through the side port and into a central dischargepassage in the outlet unit leading to the device which is to consume theLPG fuel.

Disassembly of the outlet unit from the pressure can and internal bodycauses internal pressure to move the piston to seat against the lowerend of the elastomeric sleeve to provide a check valve against escape ofLPG until the can is to be placed in use again. The piston is readilydisplaced by a conventional hollow refill probe so that the contents ofthe can can be replenished when needed. After completion of the refilloperation, the piston resumes its function as a check valve to preventescape of LPG unti the can is to be used again.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIG. 1 is a side elevation showing a preferred embodiment of thisinvention.

FIG. 2 is a sectional elevation taken substantially on the lines 22asshown in FIG. 1.

FIG. 3 is a sectional view similar to FIG. 2, showing the installationof the outlet unit.

FIG. 4 and FIG. 5 are transverse sectional details taken substantiallyon the lines 4-4 and 55, respectively, as shown in FIG. 2.

FIG. 6 and FIG. 7 are sectional details taken substantially on the lines6-6 and 77, respectively, as shown in FIG. 3.

FIG. 8 is a view similar to FIG. 3 but showing the parts in an operatingposition in which gas under pressure is being discharged from thepressure can.

FIG. 9 is a view similar to FIG. 2 showing the operation of refillingthe pressure can with LPG.

FIG. 10 is a sectional detail showing the position of the parts afterwithdrawal of the refill apparatus, and showing the piston in sealingposition within the lower end of the bore of the elastomeric sleeve.

FIG. 11 is a sectional detail showing a modified form of the invention.

FIG. 12 is a sectional view taken substantially on the lines 12-12 asshown in FIG. 11.

Referring to the drawings, a conventional metallic pressure can 10 isprovided with an end wall 1 1 which forms the can top. The can top 11 isfixed to the pres sure can by means of a conventional spun joint 9. Astationary tubularbody 12 is fixed to the end wall 11 in alignment withthe central aperture 13 and projects into the interior of the pressurecan 10. A shoulder 15 on the body is clamped between the crimped portion16 of the end wall 11 and the flange 17, and a sealing washer 18 isclamped between the body shoulder 15 and the flange 17. The stationarybody 12 is provided with internal threads 14. An elastomeric sleeve 20having a central axial bore 21 is contained within the body bore 22between the shoulder 23 and the shoulder 24. The shoulder 24 is providedby the retainer tube 25 having a press fit connection 26 with the body12. The body 12 and retainer tube 25 function as a single integral unit.

A cylindrical piston 28 having rounded ends is mechanically installedwithin the bore 21 of the elastomeric sleeve 20 and between the ends ofthe sleeve 20 after the pressure can 10 is initially filled with LPG.This initial filling is accomplished by conventional means. The diameterof the cylindrical piston 28 is greater than the initial free diameterof the bore 21 of the elastomeric sleeve 20, so that the piston isresiliently gripped within the bore 21. The parts are then in theposition shown in FIG. 2. In this position, the pressure can is sealedagainst escape of LPG under normal operating pressures. Should theinternal pressure in the can rise beyond a predetermined maximum, suchas would be occasioned by subjecting the can to excessive temperatures,the piston 28 is blown out of the bore 21 and out through the threadedopening 14 and through the can top aperture 13, permitting escape of theLPG contents of the can, and thereby avoiding an explosion of the can.

The piston 28 remains in the sealed position shown in FIG. 2 until thepressure can 10 is used to supply fuel to an external fuel-consumingdevice. The pressure can may be safely stored or transported withoutdanger of escape of LPG unless excessive temperature conditions areencountered, and in the latter event an explosion of the can isprevented by blowout of the piston 28. During this period prior to thetime of desired use of the fuel from the can, nothing projects from thecan top which might be broken off or damaged.

In order to connect the pressure can for delivery of LPG to an externalfuel-consuming device (not shown), an outlet unit generally designated31 is axially inserted into the can top aperture and threaded opening 14in the body 12.

As shown in FIG. 3, the outlet unit 31 is provided with external threads32 which engage the internal threads 14 of the stationary body 12. Asmooth cylindrical projection 33 on the outlet unit 31 extends into thebore 21 and upon turning movement of the outlet unit 31 with respect tothe pressure can and body 12, the rounded end 34 of the projectioncontacts the piston 28 and mechanically moves it out of the bore 21 ofthe elastomeric sleeve and into the bore 36 of the retainer tube 25.This bore 36 is of larger diameter-than the diameter of the cylindricalpiston 28, so that gas may pass between the piston 28 and the bore 36.The outer cylindrical surface of the projection 33 forms a seal withinthe bore 21 of the elastomeric sleeve 20 to prevent flow of gas from theinterior of the pressure can. The parts are then in the position shownin FIG. 3.

Continued turning movement of the outlet unit 31 with respect to thepressure can 10 along the threads 14, 32, causes the lower end of anarrow axially extending slot 38 to project below the lower end 39 ofthe elastomeric sleeve 20. This slot 38 may be formed by a very narrowsawcut which intersects the central axial discharge passage 40 in theprojection 33 and head 41 of the outlet unit 31. A discharge tube 43pressed into the head 41 comprises a continuation of the outlet passage40. Conventional external rings 44 on the outlet tube 43 provide aconnection for a discharge hose leading to a fuel-consuming device (notshown).

The flow rate through the discharge passage 40 is accurately regulatedby turning of the head 41. of the outlet unit 31 toexpose-the lower endof the slot 38 below the elastomeric sleeve 20 in a controlled manner.Maximum exposure of theslot 38 occurs when the lower end 47 of the skirt4 8.on the head 41 contacts the top end wall 11 of the pressure can 10,as shown in FIG. 8.

Removal of the outlet unit 31 causes the piston 28 to be moved bypressure and velocity of the gas into sealing position at the lower end39 of the elastomeric sleeve 20, as shown in FIG. 10. The normaloperating pressures within the pressure can 10 are not sufficient tomove the piston 28 completely into the bore 21. However, if excessivepressures should occur because of heat, such excessive pressures propelthe piston 28 through the bore 21 and out through the aperture 13, toprevent explosion of the can.

As shown in FIG. 9, the pressure can 10 may be refilled using aconventional hollow probe 51 carried on the end of a filler hose 52. Anenlarged portion 53 of the hollow probe 51 is smooth and is looselyreceived within the threaded opening 14 of the body 12. The cylindricalpiston 28 is displaced from sealing position at the end 39 of theelastomeric sleeve 20, either mechanically by the end of the probe 51 orby pressure of the fluid in the interior of the hollow probe. The piston28 moves to the lower end of the retainer tube but is prevented frompassing out of the tube into the interior of the can by means of thestop 54 at the end of the tube 25. Ports 55 in the stop 54 permit theflow of LPG in either direction through the stop 54. During the fillingoperation, vapors escape through the clearance space between the bodythreads 14 and the enlarged portion of the probe 53. Upon completion ofthe filling operation, the filling probe 51 is axially withdrawn and thepiston 28 returns to seat against the lower end 39 of the elastomericsleeve 20, as shown in FIG. 10. If desired, a coil compression springmight be mounted on the stop 54 within the retainer tube to supplementthe pressure force holding the piston 28 against the end 39 of theelastomeric sleeve 20.

In the modified form of the invention shown in F IGS. 11 and 12, thethin axial slot is replaced by an inclined fiat surface 57 on the outercylindrical portion of the projection 33a. This flat surface 57 mergeswith the cylindrical surface of the projection at a point spaced fromthe lower end 34a of the projection. The other end of the inclined flatsurface 57 communicates through a small radial port hole 58 with thedischarge passage 40a. The operation of this modified form of the deviceis the same as that previously described.

In a typical commercial embodiment of this invention, the piston 28 isformed of brass or aluminum, and the elastomeric sleeve 20 is formed ofa fluorocarbon elastomer having a Shore hardness of 65-70. The diameterof the cylindrical piston 28 is about 0.008 inch to 0.010 inch largerthan the normal free diameter of the bore 21.

Having fully described our invention, it is to be understood that we arenot to be limited to the details herein set forth but that our inventionis of the full scope of the appended claims.

We claim:

1. In combination: a fluid pressure can having walls provided with anaperture, a body fixed within the can and having walls defining an axialopening, an elastomeric sleeve capable of lateral distortion and fixedwithin the body and having a cylindrical bore communicating with saidaxial opening and said aperture, and a. metallic cylindrical pistonpositioned withinsaid cylindrical bore wholly between the ends of theelastomeric sleeve, and outer diameter of the piston being greater thanthe normal free diameter of said cylindrical bore, whereby the piston isresiliently gripped within the bore and seals the bore to prevent escapeof fluid pressure from the can.

2. In combination: a pressure can containing LPG and having an end wallprovided with an aperture, a tubular body fixed to the end wall andhaving walls defining an axial opening, an elastomeric sleeve capable oflateral distortion and fixed within the body and having a cylindricalbore communicating with said axial opening and said aperture, and ametallic cylindrical piston positioned within said bore wholly betweenthe ends of the elastomeric sleeve, the outer diameter of the pistonbeing greater than the normal free diameter of said bore but less thansaid axial opening in said tubular body, whereby under normal operatingtemperaturesthe piston is resiliently gripped within the bore and sealsthe bore to prevent escape of LPG, but is ejected axially from said boreand through said axial opening and aperture by excessive pressureswithin the can caused by abnormally high temperatures.

3. In combination: a pressure can having walls provided with anaperture, a body fixed within the can and having walls defining an axialopening, an elastomeric sleeve capable of lateral distortion and fixedwithin the body and having a cylindrical bore communicating with saidaxial opening and said aperture. a metallic cylindrical pistonpositioned within said bore wholly between the ends of the elastomericsleeve to prevent escape of pressure from the can, the outer diameter ofthe piston being greater than the normal free diameter of said bore sothat the piston is resilently gripped within the bore, and an outletunit having a cylindrical projection insertable axially through saidaperture and axial opening and into said bore to displace said pistonaxially from said bore, said cylindrical projection sealing within saidbore.

4. In combination: a pressure can containing LPG and having an end wallprovided with an aperture, a tubular body fixed to the end wall andhaving walls defining an axial opening, an elastom sleeve capable oflateral distortion and fixed wi tlii Hr-N n a y dt sal. bQWFQFRIFHQiQQEw Said as! opening and said aperture, a metallic cylindrical pistonpositioned within said bore wholly between the ends of the elastomericsleeve and resiliently gripped within the bore to prevent escape of LPGthrough said aperture, the outer diameter of the piston being greaterthan the normal free diameter of said bore, and an outlet unit having acylindrical projection insertable axially through said aperture andaxial opening and into said bore to displace said piston axially fromsaid bore, said cylindrical projection sealing within said bore. I

5. In combination: a pressure can having walls provided with anaperture, a body fixed within the can and having walls defining anaxial'opening, and having internal threads, an elastomeric sleevecapable of lateral distortion and fixed within the body and having anaxial cylindrical bore communicating with said axial opening and saidaperture, a metallic cylindrical piston of greater diameter than thenormal free diameter of said bore resiliently gripped within the borewholly between the ends thereof and cooperating with the elastomericsleeve to prevent escape of pressure through said body and aperture, anoutlet unit having a portion insertable through said aperture and axialopening, said portion having external threads engageable with saidinternal threads and having a cylindrical projection movable into saidbore to displace said piston axially from said bore, said cylindricalprojection sealing within said bore.

6. The combination set forth in claim 5 in which said cylindricalprojection contains a narrow axially extending sawcut near theprojecting end thereof communicating with an axial discharge passage insaid projection, the maximum length dimension of said sawcut being onthe exterior surface of said projection.

7. The combination set forth in claim 5 in which said cylindricalprojection has an inclined flat exterior surface near the projecting endthereof communicating withan axial discharge passage in said projection.

1. In combination: a fluid pressure can having walls provided with anaperture, a body fixed within the can and having walls defining an axialopening, an elastomeric sleeve capable of lateral distortion and fixedwithin the body and having a cylindrical bore communicating with saidaxial opening and said aperture, and a metallic cylindrical pistonpositioned within said cylindrical bore wholly between the ends of theelastomeric sleeve, and outer diameter of the piston being greater thanthe normal free diameter of said cylindrical bore, whereby the piston isresiliently gripped within the bore and seals the bore to prevent escapEof fluid pressure from the can.
 2. In combination: a pressure cancontaining LPG and having an end wall provided with an aperture, atubular body fixed to the end wall and having walls defining an axialopening, an elastomeric sleeve capable of lateral distortion and fixedwithin the body and having a cylindrical bore communicating with saidaxial opening and said aperture, and a metallic cylindrical pistonpositioned within said bore wholly between the ends of the elastomericsleeve, the outer diameter of the piston being greater than the normalfree diameter of said bore but less than said axial opening in saidtubular body, whereby under normal operating temperatures the piston isresiliently gripped within the bore and seals the bore to prevent escapeof LPG, but is ejected axially from said bore and through said axialopening and aperture by excessive pressures within the can caused byabnormally high temperatures.
 3. In combination: a pressure can havingwalls provided with an aperture, a body fixed within the can and havingwalls defining an axial opening, an elastomeric sleeve capable oflateral distortion and fixed within the body and having a cylindricalbore communicating with said axial opening and said aperture, a metalliccylindrical piston positioned within said bore wholly between the endsof the elastomeric sleeve to prevent escape of pressure from the can,the outer diameter of the piston being greater than the normal freediameter of said bore so that the piston is resilently gripped withinthe bore, and an outlet unit having a cylindrical projection insertableaxially through said aperture and axial opening and into said bore todisplace said piston axially from said bore, said cylindrical projectionsealing within said bore.
 4. In combination: a pressure can containingLPG and having an end wall provided with an aperture, a tubular bodyfixed to the end wall and having walls defining an axial opening, anelastomeric sleeve capable ble of lateral distortion and fixed withinthe body and having a cylindricalbore communicating with said axialopening and said aperture, a metallic cylindrical piston positionedwithin said bore wholly between the ends of the elastomeric sleeve andresiliently gripped within the bore to prevent escape of LPG throughsaid aperture, the outer diameter of the piston being greater than thenormal free diameter of said bore, and an outlet unit having acylindrical projection insertable axially through said aperture andaxial opening and into said bore to displace said piston axially fromsaid bore, said cylindrical projection sealing within said bore.
 5. Incombination: a pressure can having walls provided with an aperture, abody fixed within the can and having walls defining an axial opening,and having internal threads, an elastomeric sleeve capable of lateraldistortion and fixed within the body and having an axial cylindricalbore communicating with said axial opening and said aperture, a metalliccylindrical piston of greater diameter than the normal free diameter ofsaid bore resiliently gripped within the bore wholly between the endsthereof and cooperating with the elastomeric sleeve to prevent escape ofpressure through said body and aperture, an outlet unit having a portioninsertable through said aperture and axial opening, said portion havingexternal threads engageable with said internal threads and having acylindrical projection movable into said bore to displace said pistonaxially from said bore, said cylindrical projection sealing within saidbore.
 6. The combination set forth in claim 5 in which said cylindricalprojection contains a narrow axially extending sawcut near theprojecting end thereof communicating with an axial discharge passage insaid projection, the maximum length dimension of said sawcut being onthe exterior surface of said projection.
 7. The combination set forth inclaim 5 in which said cylindrical projection has an inclined flatexterior surface near the projecting end tHereof communicating with anaxial discharge passage in said projection.